If you are installing FTM 2012 on a new computer you don't have to touch FTM 2006 which can remain forever on your old computer.
The only difference in procedure is that using Windows Explorer (not Internet Explorer) on your old computer you need to copy your FTM 2006 file (the one ending in .FTW) onto a memory stick or CD or some suitable method to transfer the file to the new computer.
Once you have copied it to the USB memory stick (or thumb drive as some people call them), you then need to copy it from the USB memory stick to a suitable folder on your new computer. It doesn't matter where you copy it to, (and again you use Windows Explorer), but I would suggest that you create a new folder on the C Drive of the new computer and call it something appropriate like' "My Family History files" .
Put the .FTW file from FTM 2006 there and then from FTM 2012 Plan View>New File>Import from an existing file, and navigate to where you have placed your .FTW file from your old computer
In copying your .FTW file from FTM 2006, please use Windows Explorer for the .FTW file. Do not use FTM 2006 backup as this will create a .FBC file which FTM 2012 cannot read!!!!!
All of this is really very straightforward and much easier to do than to describe